I tried the Rocs for a while in Tanaris but kept being overwhelmed by adds while I was fighting them. I was also a level 40 Paladin on the Cooking quest. By accident, I discovered that the Owlbeasts in the Hinterlands drop them too. I was doing a quest called something like "Favored of Elune" where you gather feathers dropped from those beasts. The critters in the Hinterlands seem to be a bit more spread out and you can fight them one at a time. Not real easy soloing but doable.